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. w m E n Q T N .62 N M u I Q S m A Z (No Model.)

J. J. TANNER.

EXTENSION CLAMP.

Patentd Jan. 13,1891.

WITNESSES:

UNITED STATES PATENT Gretel-2..

JESSE J. 'TANNER, OF ONEIDA, NEV YORK, ASSIGNOR OF ONE-HALF TO ROBERT J. FISH AND DANIEL C. BURKE, BOTH OF SAME PLACE.

EXTENSlON-C'LAM P.

SPECIFICATION forming part of Letters Patent No. 444,510, dated January 13, 1891.

Application filed March 5, 1890. Serial No. 342,707. (No model.)

To all whom it may concern:

Be it known that I, JEssE' J. TANNER, of Oneida, in the county of Madison, in the State of New York, have invented new and useful Improvements in Extension-Clamps, of which the following, taken in connection with the accompany ng drawings, is a full, clear, and exact description.

This invention relates to the class of clamps which are extensible in length and are chiefly employed by moldcrs, carpenters, and cabinet-makers; and the invention consists in the improved construction and combination of parts hereinafter fully described, and set forth in the claims.

In the annexed drawings, Figure 1 is a side view of a clamp embodying my improvements, the central portion of the clamp-bar being broken away to bring the end portions within the field of illustrations. Fig. 2 is a vertical longitudinal section of the same. Fig. 3 is a plan view; and Figs. at and 5 are enlarged transverse sections, respectively, on lines a: a: and y y, Fig. 1.

Similar letters of reference indicate corresponding parts.

0 denotes the clamp-bar, which I preferably form with a longitudinal channel and with slots or perforations c c c in its bottom. Oneend of the said bar has rigidly attached to it or formed integral with it a head 7L, preferably projecting downward from the bottom of the bar. The top portion of the interior of this head is formed with a smooth seat h for the clampingscrew 3, which extends through said head in line with the longitudinal groove of the bar a. From the screwseat 7t downward is a recess 1* in the head It, and the bottom of this recess is formed with an inclined way 1', extending to the under side of the screw. The sides of the recess 7' adjacent to the inclined way i are formed with grooves Z 7, which are parallel with said way.

n represents a nut-section adapted to e11- gage nearly or quite half of the circumference of the screw .9. This nut-section slides on the inclined way i, and is formed with side proj ections n n, which enter the grooves ll, and thus guide said nut-section on the inclined wav.

By means of asuitable handle t, extending outward from the nut-section, the latter can be pushed up and into engagement with the under side of the screw 5 when desired to employ the clamp as hereinafter described. The nut-sectionhas sufficient play lengthwise of the inclined way i to allow it to move out of engagement with the screw, and .in order to prevent the nut-section from dropping completely out of the head h I form the bottom of the inner end of the nut-section with a downwardly-projecting stop 0, and insert in the way i a plate 19, which I detachably con meet to the head 71; by a screw 0, passing up through the bottom of the head h and enteringa screw-threaded eye in the plate. To the outer end of the screw 8 I swivel a jaw 61, preferably by means of a pin D, passing transversely through the base of the jaw and tangentially through a circumferential groove D in the surface of the shank of the screw. Said shank projects sufficiently from the outer end of the jaw d to allow a crank or suitable handle I to be attached to the screwshank for turning the screw.

drepresents the jaw, which is connected longitudinally adjustably to the bar a. This jaw projects from a shoe 6, which is preferably formed integral with it and embraces the bottom and sides of the bar a. The end of the shoe 6 nearest the end of the screw sis formed with a lugf and a head f on said lug, both of which latter are adapted to enter into the slot 0. Each of the slots 0 c c is tapered in width toward the end of the bar a farthest from the screw 5. The small end of the slot allows the lug f to enter, but is narrower than the head f, and thus the shoe e is securely held on the bar a. when strain is applied to the jaw (Z in the operation of the clamp. A spring g, attached to the end of the shoe farthest from the screw 5 and bearing against the under side of the bar a, serves to sustain the shoe and jaw (Z in their normal position when the lug f is withdrawn from the slot 0.

The described clamp is operated as follows:

The jaw d is first set in such a position on the bar a as to render thatportion of said bar which is in front of the jaw somewhat shorter than the article to be gripped by the clamp.

'lhen, while holding the jaw (Z against. one edge of the aforesaid article, the nut scction n is drawn out of engagement with the screw s. The latter can then he pushed along to bringthe jaw d up against the opposite edge of the article to be gripped, and by pushing the nut-section a into engagement with the screw and then turning the latter the jaw d tightened in its hold on the aforesaid article.

Thus the adjustment of the clamp is greatly facilitated. It will also be observed that by the attachment of thejaw d to the outer end of the screw .9 I obtain a greater range of adjustment.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, 1's

1. The jaw (1, formed with the shoe 6, lug f,

JESSE J. TANNER. [L. s]

Witnesses:

JOSEPH BEAL, B. RATNEUR. 

